Resilient electrical contact

ABSTRACT

An electrical contact for an electrical wire having a first slotted member for receiving the wire and a pair of supporting members integrally formed with, and disposed upon opposite sides of the slotted member for providing a strain-relief function for the wire, the configuration of the contact being S-shaped in cross-section. A hand tool is provided for inserting the wire within the contact, the tool having pivotable and fixed hand-grip members for actuating a spring biased reciprocable ram and anvil assembly. Operation of the hand-grip members actuates the ramanvil assembly which inserts the wire within the contact while simultaneously releasing the tool from the contact.

United States Patent 91 Demler, Sr. et a1.

[ RESILIENT ELECTRICAL CONTACT [75] Inventors: Henry William Demler, Sr.,

Lebanon; Paul Joseph Minchhoff,

Harrisburg, both of Pa.

[73] Assignee: AMP Incorporated, Harrisburg, Pa.

[22] Filed: Aug. 22, 1972 [2]] Appl. No.: 282,823

[52] US. Cl. 339/17, 339/97 R, 339/275 B [51] Int. Cl. H0lr 11/20, H05k l/O2 Field of Search. 339/95-99, 339/103, 107, 276T, 256-258, '17 R, 17 C,- 275 [5 6] References Cited UNITED STATES PATENTS 3,683,319 8/1972 Vigeant et a1 339/97 R 3,636,500 1/1972 Sedlacek 339/97 R 3,521,221. 7/1970 Lenaerts et a1..... 339/97 P 3,605,071 9/1971 Sedlacek 339/97 P 2,694,189 11/1954 Wirsching 339/97 R FOREIGN PATENTS OR APPLICATIONS 1,640,633

10/1969 cerman wj. ..339/97R Apr. 16, 1974 1,963,313 6/1971 Germany 339/97 R Primary Examiner-Bobby R. Gay Assistant Examiner-Terrell P. Lewis Attorney, Agent, or Firm-Gerald K. Kita, Esq.

[5 7] ABSTRACT rocable ram and anvil assembly. Operation of the hand-grip members actuates the ram-anvil assembly which inserts the wire within the contact while simultaneously releasing the tool from the contact.

8 Claims, 10 Drawing Figures PATENTEUAPR 16 I974 SHEET 3 BF 6 o w m N RESILIENT ELECTRICAL CONTACT BACKGROUND OF THE INVENTION multi-step mechanical aids. In order to satisfy such requirement, prior art devices have been utilized with varying degrees of success which include a U or V-shaped grooved conductive member for cutting through the insulation and resiliently holding and completing a conductive path with the wire. Although such prior art devices have been generally successful, the structural integrity of such devices has not been wholly satisfactory and in fact usually requires the contacts to be mounted in a housing for support. A further problem with such devices resides in that they-are generally susceptible to a high level of strain in the wire at the contact point resulting in some occurrances of wire dislodgement or breakage. 1

SUMMARY OF THE INVENTION Accordingly, one object of this invention is to provide a new and'improved electrical contact having good structural integrity.

Another object of the invention. is the provision of a novel electrical contact having good structural integrity without the requirement of a housing.

Still another object of the present invention is to provide a newand improved electrical contact which provides strain relief for a wire inserted therein.

A still further object of the present invention is the provision of a new and improved electrical contact which is relatively small and economical to manufacture.

A still further object of the present invention is the provision of a new and improved electrical contact which is readily adaptable for point-to-point wiring, with a plurality of contacts being mounted in a printed circuit board (PC. board).

Another object of the present invention is to provide a tool for electrically connecting individual wires or wires of a ribbon cable from point-to-point locations defined by a plurality of contacts according to the present invention mounted in a PC. board, the tool being capable of cutting wires at selected contacts or alternatively inserting wires into the contacts without cutting.

One further object of the present invention is the. provision of a novel electrical contact having high structural integrity and a novel tool for electrically connecting a wire in such contact and for selectively cutting off .wire at the contact.

BRIEF DESCRIPTION OF THE DRAWING A more complete appreciation of the invention and many of the attendant advantages thereof will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawing, wherein:

FIG. 1 is a plan view of the connector of the present invention attached to a carrier strip at one stage of manufacture thereof;

FIG. 2 is a perspective view of the electrical contact of the present invention;

FIG. 3 is a top view of the contact of the present invention as viewed in the direction of the arrow 3 shown in FIG. 2; I

FIG. 4 is a partial sectional view taken along the line 4--4 of FIG. 3. showing one insulation contact;

FIG. 5 is a partial sectional view taken along the line 55 of FIG. 2, with parts not shown, of the wire contact of the present invention;

FIG. 6 is a side view of the tool of the present invention with parts in section;

FIG. 7 is an exploded view of the operative portions of the tool of FIG. 6;

FIG. 8 is a sectional view of the operative portions of the tool of FIG. 6 in a first position illustrating the assembly of a wire to a contact;

FIG. 9 is a sectional view of the operative portions of the tool of FIG. 6 in a second position of the assembly of a wire in a contact; and,

FIG. 10 is a sectional view of the operative portions of the tool of FIG. 6 illustrating the combination of assembling a wire with the contact and cutting off the DESCRIPTION OF THE PREFERRED EMBODIMENT has been formed by providing a break line 18 between the contact 12 and the carrier strip 14.

A center contact arm 20 is provided at the base of the contact for extension through a PC board to the like and may consist of any known contact shape. A first bifurcated portion 22 provides a wire contact which is in longitudinal alignment with the center contact arm 20 and a pair of symmetrically designed insulation contacts indicated generally at 24 and 26 are provided at opposed sides of the wire contact 22. In order to form the contact into the shape as actually used, the insulation contacts 24 and 26 are respectively bent in opposed directions so as to be in alignment with wire contact 22, as shown in FIGS. 2 and 3.

The contact 12 when in the fully formed condition, as shown in FIGS. 2 and 3, is capable of providing good structuralintegrity due to the generally S-shaped construction, and can be used with non-insulated wire, insulated wire, ribbon type cable and the like. The bifurcated wire contact 22 is provided with a contact wedge slot 28 having a width of such dimension that the wire contact will cut through any insulation about the wire and will compress opposite sides of the wire as the insu lated wire is forcibly inserted into the wedge slot. The wire is compressed to an oval shape and the opposite sides thereof are wiped upon forcible insertion in the slot, to provide wiping of the wire surfaces and the slot surfaces for good electrical conductivity, as shown most particularly in FIG. 5. Also the outer sides 30 of the contact act as opposed resilient cantilever beams which, upon forcible insertion of the wire between the beams, provide resilient cantilever compression on the inserted wire to assure forcible contact with the wire for good conductivity. The outer sides 30 of the wire contact are substantially straight so as to provide strength to the wire contact while the contact retains a generally resilient nature. The knife edge 16 provided on each of the bifurcated portions of the wire contact enable the contact to cut through the insulation on ribbon type cable when the contact is used in conjunction therewith. The knife edge 16 is outwardly angled as at 32 so as to provide a notch capable of easily receiving an insulated wire and for funneling the wire into the slot 28.

Insulation contacts 24 and 26 are each bifurcated and provided with central grooves or slots 34 and 36, respectively, which are in alignment with contact wedge slot 28 such that a wire received in the center slot would be likewise received in the grooves or slots 34 and 36 with the wire in a straight position such that strain relief and resistance to pull-out would be provided therefor. The width of slots 34'and 36 is dimensioned such that a wire placed along the slots would be supported by its insulation to adequately provide strain relief and resist pull-out of the wire from the contact 22 as shown in FIG. 4. Each of the bifurcated portions of the insulation support contacts is provided with an entrance angle portion 38 and an outside angle portion 40 meeting at a point 42 such that when used with wires in side-by-side relationship in an insulation covering in a ribbon type cable 43 or the like, instead of individual insulation covered wires, the piercing points 42 easily cut through the insulating portions 45 of the ribbon type cable and the entrance angles funnel the conductor into the insulating support grooves 34 and 36. As shown in FIG. 2, the piercing points 42 are on both sides of and extend above the central contact slot 32. As the ribbon type cable is forced into contact with the terminal 26, the points 42 will initially engage and then cut through the insulating portions 45, thereby dividing out a single wire from the insulating portions 45. The single wire is then free from the insulation portions 45 for forcible insertion into the contact slot 32. Locating tabs 44 and 46 are integrally formed and downwardly extended at each insulation contact 24 and 26, respectively, and are provided with a flat base portion for engagement with a PC board or the like. As shown in FIG. 4, the individual wire 47 in the grooves 34 and 36 is in compression but in less compression than in the slot 28.

It can be seen that the unique construction of the contact of the present invention provides good structural integrity due to the generally S-shape, and provides strain relief for a wire held by and anchored in the insulation contacts 34 and 36 while the wire is in good electrical contact with the contact wedge slot 28. Since good structural integrity is provided in the construction of the contact of the present invention, and since the wire is effectively anchored to the contact support grooves 34 and 36 on either side of the contact slot 28, resistance to pull-out of the wire from either side of the contact slot 28 is assured, and there is no necessity for providing a separate housing or support for the contact, as has been generally necessitated by the prior art devices.

It is noted that with reference to FIGS. 8 through 10, that the triple wedge contacts of the present invention are typically inserted within through holes in a PC board with their locating tabs 44 and 46 in appropriate position such that the tabs abut the PC board thereby positioning the contacts at a predetermined height above the board.

In order to properly position the wire within the miniaturized contact of the present invention, it is hightly advantageous to utilize the particular hand tool having the unique and novel configuration disclosed in FIGS. 6 through 10. The unique tool disclosed therein comprises a housing 48 which has a handle 50 integral therewith and a hand grip 52 which is pivotally mounted with respect to the housing 48 and handle 50 by means of pivot pin 54. An actuating extension 56 is integrally fixed upon hand grip 52, one surface of extension 56 being adjustably abutted by a set screw 58 which determines the extent of travel of extension 56 and hand grip 52 in one direction. Defined within housing 48 is a first cylindrical bore 60 and a second reduced cylindrical bore 62 for receiving a cylindrical ram 64 therein. The rear terminal portion of ram 64 comprises a flanged section 66 which abuts another surface of actuating extension 56. Surrounding cylindrical ram 64 and seated within the larger bore 60 is a coil compression spring 68, the ends of spring 68 abutting flange portion 66 and the reduced diameter portion of bore 60 and 62, spring 68 thereby maintaining ram 64 in its retracted mode upon the release of hand grip 52 as shown in FIG. 6.

The forward operative portion of the tool includes a pusher member 70, a contact holder'72, and a wire cutter 74. Contact holder 72 is fixed relative to housing 48 via an internally threaded sleeve 76. Referring more particularly to FIGS. 7 and 8, it is seen that the forward portion of contact holder 72 comprises a pair of resilient holding fingers 78. Contact holder 72 additionally comprises a first bore having a diameter sufficient for retaining the larger diameter of the ram 64. Ram 64 further comprises a flattened area 82 for cooperation with a retaining pin 84 situated within the bore 80, pin 84 thereby preventing any rotation of ram 64 relative to bore 80. Contact holder 72 additionally comprises second, third and fourth cylindrical bores 86, 88 and 90, of consecutively diminished diameters, the third cylindrical bore 88 further containing a generally ovoid aperture 92 for providing flexures 94 which in turn resiliently bias holding fingers 78. Holding fingers 78 define therebetween a wire receiving slot 96. A retaining pin 98 laterally disposed within the forward portion of ram 64 secures a pusher element 100 within an aperture formed within such forward portion, pusher element 100 further containing an anvil member 110.

Referring now to FIG. 8, a wire 112 is disclosed as being positioned within wire receiving slot 96 in abutting relationship with the forward portion of anvil which is in its fully retracted mode. When pressure is exerted upon an end section of housing 48 in a longitudinal direction relative to the .housing, holding fingers 78 will come into contact with the outside angle portions 40 of electrical contact 12 via camming surfaces 114. Continued application of pressure, causes camming surfaces 114 to slide upon angle portions 40 in a generally longitudinal direction, such action simultaneously spreading apart fingers 78, fingers 78 further sliding upon exterior portions 41 of contact 12 which are parallel to the longitudinal axis of contact 12, the sliding action in the spread mode continuing until the fingers 78 reach the lower terminal portion 43 of contact 12, whereupon fingers 78 will radially contract so as to lock themselves with contact 12, thereby preventing removal of the toolrelative to the contact. It is noted that the locating tabs 44 and 46 are appropriately positioned relative to the tool such that the fingers 78 are enabled to lock with the contact 12 and in addition, the anvil l 10, wire 112, and the grooves 28, 34, and 36, are all in proper alignment.

Referring again to FIG. 6, as the hand grip 52 is squeezed relative to handle 50, extension member 56 pivots around pivot pin 54 thereby abuttingflange portion 66 of ram 64 so as to longitudinally move ram 64 against the action of coil spring 68. Movement of ram 64 in turn causes longitudinal movement of anvil member 1110, thus advancing wire 112 from its position disclosed in FIG. 8 to that disclosed in FIG. 9. Simultaneously with the aforementioned action, a pair of ram cam surfaces 116 abuts the upper portion of slot 96 so as to laterally spread the resilient fingers 78, thus releasing the tool from the contact 12.

Wire cutter 74 consists of a tubular sleeve having a first bore portion 118 for surroundingly engaging an outer wall protion 120 of contact holder 72, the sleeve being additionally provided with a pair of slots 112 which respectively receive the pair of pins 124 which are fixed within outer wall I such that the wire cutter 74 may be rotated relative to contact holder 72. Extending downwardly from the sleeve of wire cutter 74 is a pair of cutting members 126 and 128, the cutting members being identical in construction but oppositely faced. Each of the cutting members 126 and 128 includes a pair of cutting edges 130 and 132 such that by rotating the member 74 either clockwise or counterclockwise, one side of the wire can be selectively aligned with the cutting edges. As the ram 64 is moved from the operative position shown in FlG. 8 to the operative position shown in FIGS. 9 or 10, the wire would first be cut, as shown in FIG. 10, and would secondly be inserted within the grooves of the contact. The tool thus is utilized to bridge between and electrically connect a wire from point-to-point locations defined by two or more spaced contacts 12 mounted on a PC board without a need for severing the wire. Alternatively, the wire may be connected to a selected contact 12 on the PC board and then severed, thus ending the wire at its connection to the selected contact 12.

Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein. For example, although a specific novel tool has 6 been disclosed for inserting the wire within the contact of the present invention, it is to be noted that the wire could be inserted by hand or by other tools. Also, for

example, the slot portions 28 and 34 and 36 may be tapered in width such that a wire being progressively forced toward the bottom of the slot becomes progressively compressed in narrower widths of the tapered slots;

What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. In the combination of the printed circuit board and an electrically conducting contact mounted thereto, the combination comprising:

an elongated portion of said contact mounted fixedly in said printed circuit board,

a generally S-shaped portion of said contact integral with said elongated portion and mounted adjacent one surface of said printed circuit board,

a pair of outer contact portions of said S-shaped portion being bifurcated with slots for wedgingly receiving an insulated wire therein,

a centralprojecting contact portion of said S-shaped portion having a slot therein adapted for wedgingly receiving an insulated wire therein,

the slot of said central contact portion being adapted to slice through the insulation of an insulation covered wire wedgingly received in said slot to establish electrical connection between the insulation covered wire and the edges of said central contact portion along the slot thereof,

the two outer contact portions of said S-shaped portion projecting above the central portion, and

an enlarged wire receiving opening in each outer contact portion, each of said openings being located outwardly above the central contact portion of said S-shaped portion.

2. The structure as recited in claim 1, wherein, said outer contact portions of said S-shaped portion are provided with points on either side of said wire receiving opening.

3. An electrical terminal adapted for insertion in a printed circuit board, comprising:

a central elongated arm portion adapted for insertion in a printed circuit board,

a first contact portion integral with said arm portion and projecting above said arm portion,

said first contact portion having a slot therein communicating with one side of said contact portion,

the sides of said first contact portion adjacent said slot defining resilient cantilever beams, whereby an insulation covered wire may be forcibly inserted into said slot from one side of said first contact portion and retained in compression between said can- I tilever beams with the beams slicing through the insulation for electrical contact with the wire,

a pair of additional contact portions integral with said first contact portion, said first contact protion being disposed between said additional contact portions,

each said additional contact portion having a slot therein extending from one side thereof, whereby an insulation covered wire may be anchored and supported by its insulation within the slot of each said additional contact portion to resist pull-out of the wire from the first contact portion, and

the slot of said first contact portion being in alignment with the slot of each said additional contact portion, whereby a substantially straight length of an insulation convered wire may be extended through each of said slots.

contact portion. 5. In the combination of a printed circuit board and a contact as recited in claim 1, the improvement comprising:

each said outer contact portion having a depending projecting tab in engagement on said printed circuit board for location of said contact against said printed circuit board. 6. An electrical contact, the combination comprising:

a pair of wire-receiving strain relief members on said contact,

a wire receiving contactelement disposed between said strain relief members,

each said strain relief members having a slot therein, the slots of said strain relief members being in alignment with each other,

said wire receiving contact element having a slot therein in alignment with each slot of said strain relief members,

the slot of said wire receiving contact element being of lesser width than either slot of said strain relief members, whereby a relatively straight length of insulation covered wire may be wedgingly received in the aligned slots, with the wire receiving contact element adapted for slicing through the insulation for electrical contact with the wire, and with the strain relief members anchoring the insulation covered wire on either side of said wire receiving contact element;

said wire receiving contact element being integral with each said strain relief member, and

an elongated portion integral with said wire receiving contact element and depending therefrom to provide a mounting arm.

7. The structure as recited in claim 6, wherein, each said wire receiving strain relief members includes a projecting portion which projects above said wire receiving contact member, and

an enlarged entrance opening portion provided in each projecting portion of a corresponding strain relief member,

each said enlarged entrance opening portion communicating with said slot of a corresponding strain relief member.

8. The structure as recited in claim 7, wherein, said projecting portion of each strain relief member is pointed on either side of a corresponding enlarged entrance opening portion.

2% UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Ratent NO Dated I nventofls) HENRY WILLIAM DEMLER, SR PAUL JOSEPH MINCHLOFF It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 6, claim 1, line 8, "the", second occurrence,

should be a Column 6 claim 1, line 29, after "central" insert contact Column 6, claim 3, line 51;, "protion" should be portion Signed and sealed this 3rd day of September 1974 Attestz McCOY M. GIBSON, JR. C. MARSHALL DANN Attesting Officer Commissioner of Patents 

1. In the combination of the printed circuit board and an electrically conducting contact mounted thereto, the combination comprising: an elongated portion of said contact mounted fixedly in said printed circuit board, a generally S-shaped portion of said contact integral with said elongated portion and mounted adjacent one surface of said printed circuit board, a pair of outer contact portions of said S-shaped portion being bifurcated with slots for wedgingly receiving an insulated wire therein, a central projecting contact portion of said S-shaped portion having a slot therein adapted for wedgingly receiving an insulated wire therein, the slot of said central contact portion being adapted to slice through the insulation of an insulation covered wire wedgingly received in said slot to establish electrical connection between the insulation covered wire and the edges of said central contact portion along the slot thereof, the two outer contact portions of said S-shaped portion projecting above the central portion, and an enlarged wire receiving opening in each outer contact portion, each of said openings being located outwardly above the central contact portion of said S-shaped portion.
 2. The structure as recited in claim 1, wherein, said outer contact portions oF said S-shaped portion are provided with points on either side of said wire receiving opening.
 3. An electrical terminal adapted for insertion in a printed circuit board, comprising: a central elongated arm portion adapted for insertion in a printed circuit board, a first contact portion integral with said arm portion and projecting above said arm portion, said first contact portion having a slot therein communicating with one side of said contact portion, the sides of said first contact portion adjacent said slot defining resilient cantilever beams, whereby an insulation covered wire may be forcibly inserted into said slot from one side of said first contact portion and retained in compression between said cantilever beams with the beams slicing through the insulation for electrical contact with the wire, a pair of additional contact portions integral with said first contact portion, said first contact protion being disposed between said additional contact portions, each said additional contact portion having a slot therein extending from one side thereof, whereby an insulation covered wire may be anchored and supported by its insulation within the slot of each said additional contact portion to resist pull-out of the wire from the first contact portion, and the slot of said first contact portion being in alignment with the slot of each said additional contact portion, whereby a substantially straight length of an insulation convered wire may be extended through each of said slots.
 4. The structure as recited in claim 3, wherein, each said additional contact portion having an enlarged entrance portion opening into said slot, each said additional contact portion projecting above said first contact portion, whereby an insulation covered wire may be received into said enlarged entrance portions projecting above said first contact portion.
 5. In the combination of a printed circuit board and a contact as recited in claim 1, the improvement comprising: each said outer contact portion having a depending projecting tab in engagement on said printed circuit board for location of said contact against said printed circuit board.
 6. An electrical contact, the combination comprising: a pair of wire-receiving strain relief members on said contact, a wire receiving contact element disposed between said strain relief members, each said strain relief members having a slot therein, the slots of said strain relief members being in alignment with each other, said wire receiving contact element having a slot therein in alignment with each slot of said strain relief members, the slot of said wire receiving contact element being of lesser width than either slot of said strain relief members, whereby a relatively straight length of insulation covered wire may be wedgingly received in the aligned slots, with the wire receiving contact element adapted for slicing through the insulation for electrical contact with the wire, and with the strain relief members anchoring the insulation covered wire on either side of said wire receiving contact element; said wire receiving contact element being integral with each said strain relief member, and an elongated portion integral with said wire receiving contact element and depending therefrom to provide a mounting arm.
 7. The structure as recited in claim 6, wherein, each said wire receiving strain relief members includes a projecting portion which projects above said wire receiving contact member, and an enlarged entrance opening portion provided in each projecting portion of a corresponding strain relief member, each said enlarged entrance opening portion communicating with said slot of a corresponding strain relief member.
 8. The structure as recited in claim 7, wherein, said projecting portion of each strain relief member is pointed on either side of a corresponding enlarged entrance opening portion. 